Conventional rotators of the above type comprise two types of conduits, viz. a first pair of hoses for supplying (supply and evacuation) the rotor working chamber with hydraulic oil, and a second pair of hoses for supplying one or more hydraulic cylinders for the moving parts of the working implement, viz. via the swivel connection and the ducts opening thereinto and extending inwardly through the pivot axis of the rotator down to suitable connections on the implement. Both pairs of hoses are connected to the outer side of the rotator top via protruding angular nipples which of necessity are mounted on the outside of the essentially cylindrical surface extending downwardly a distance from the flat upper side of the rotator housing because the space above the flat upper side is mainly taken up by the joint by which the rotator is attached to the crane tip. In the last few years, the hydraulic oil supply hoses to the working implement have been run from the pump and the associated tank on the vehicle which carries the crane, directly to the working implement, and not via the swivel connection in the rotator. In these cases, the connection holes for this pair of hoses were plugged. Nevertheless, there always remained on the housing or the top of the rotator the two nipple-connected oil supply hoses to the rotator proper, and in practice these hoses constitute a problem of considerable difficulty when the working implement is a tree-processing unit, for example a grapple harvester which, on certain occasions, must hold a stem in a vertical position during movement from one angular position to another by means of the rotator. On such occasions, it frequently happens that the stem comes into contact both with the nipples radially protruding from the rotator top and with the hoses connected with the nipples. As a result, damage is done not only to the stem (gashes in the surface wood with the ensuing loss of quality) but also to the hoses and the nipples. This means that the nipples must be frequently serviced, which is expensive, and if the damage is so serious that leakage occurs, the tree-processing unit is no longer safe to operate.